Tap Water vs Distilled Water
Water covers more than 70% of the earths’ surface. From this, a larger portion of water is in the oceans and seas, and that is about 97%. Rivers, lakes, and ponds have 0.6% of water, and about 2% is in polar ice caps and glaciers. Some amount of water is present in the underground, and a minute amount is in the gas form as vapors and in clouds. Among these, there is less than 1% of water left for direct human use.
Water is used for many purposes in a laboratory. Water from rivers, lakes, or ponds contains many things like microorganisms, suspended particles, ions, dissolved gases, etc. Rain water also contains many things other than water molecules. Even the tap water which is distributed after purification has many dissolved compounds. These dissolved compounds may change the properties of the water.
Water is a clear, colorless, tasteless, and odorless liquid. Pure water should have a neutral pH, whereas the water we are taking from various sources may be slightly acidic or basic. However, due to the impurities in the water, we can’t use them for certain purposes. In experiments, where accurate measurements have to be taken, purified water should be used. For example, if an acidity of a sample has to be measured in a titrimetric method, then very pure water should be used in the process from cleaning the glassware to making solutions, etc. Otherwise, using normal water will give an error in the measurements. Distilled water is a pure form of water which can be used in such occasion.
Tap water is supplied to our houses and offices via a tap and it is readily available for any usage. Tap water is purified to some extent, so that it is healthy to drink and use for any other purpose. This water is pumped from a lake, river or such place and then treated in a plant.
Water treatment process involves water collection, storage, treatment and distribution steps. This is done by a government agency. During the treatment process, microorganisms and other waste is removed from water in various ways. Chemicals like chlorine are added to kill the germs. This water is constantly checked for microorganisms, which cause water borne diseases. However, when distributing, it may associate with some impurities. Therefore, it is advised to the general public to boil and cool water or filter it again before consumption.
In distilled water, the impurities are removed by distillation. The basis of distillation relies on the fact that other molecules and microscopic impurities in the water are heavier than the water molecules. Therefore, when distilling, only water molecules will evaporate. Water boils at 100 oC and water molecules will evaporate. Water steam is then allowed to travel inside a condensation tube where flow of water will absorb the heat in steam and make it condensed. Then the condensed water drops can be collected into another clean container. This water is known as distilled water.
Distilled water should contain only water molecules without any bacteria, ions, gases, or other contaminants. It should have a pH of 7, which indicates that the water is neutral. Distilled water has no taste since all the minerals have been removed, but it is safe to drink. However, distilled water is mainly used for the research purposes.
Tap Water vs Distilled Water
- Distilled water doesn’t contain any impurity, but tap water does.
- Distilled water is not suitable for consumption as it may not have necessary nutrients (ion) needed for the body.
- Distilled water has a pH of 7 whereas pH of tap water may have a value lower than that.